Device for adjusting the spring force on folding rollers

ABSTRACT

A device for adjusting the spring force pressing two axially parallel folding rollers, which comprises a shaft and two folding rollers having parallel axes and supported in swivel bearings. An abutment is spaced apart from each of the swivel bearings and mounted on the shaft. A compression spring is disposed between each of the folding rollers and an abutment. Two side walls are provided. The shaft has a thread at each of its ends. One of the ends of the shaft is threaded in a bore of one of the side walls. The other of the ends of the shaft is threaded in a threaded bore of the bushing. The bushing is disposed non-rotatably and axially displaceably in a bore of the other of the side walls, and the pitch of the threaded bore of the bushing is twice as great as the pitch of the threaded bore of said one of the side walls.

United States Patent 1191 Hertrich Jan. 22, 1974 [5 1 DEVICE FOR ADJUSTING 'rn sPRmc FORCE 0N roumvc ROLLERS [75] Inventor: Klaus Hertrich, Gohrenz, Germany 221 Filed: o1.1s,1971

211 Appl.No.: 189,848

[58] Field of Search. 100/86, 89, 99, 169, 171, 176; 68/248, 257, 262 R, 262 A, 262 B; 226/177,

l/l967 Germany 7/1946 Great Britain 68/262 A Primary Examiner-Harvey C. l-lornsby Assistant Examiner-Philip R. Coe Attorney, Agent, or Firm-Ernest G. Montague [57] ABSTRACT A device for adjusting the spring force pressing two axially parallel folding rollers, which comprises a shaft and two folding rollers having parallel axes and supported in swivel bearings. An abutment is spaced apart from each of the swivel bearings and mounted on the shaft. A compression spring is disposed between each of the foldingrollers and an abutment. Two side walls are provided. The shaft has a thread at each of its ends. One of the ends of the shaft is threaded in a bore of one of the side walls. The other of the ends of the shaft is threaded in a threaded bore of the bushing The bushing is disposed non-rotatably and axially displaceably in a bore of the other of the side walls, and the pitch of the threaded bore of the bushing is twice as great as the pitch of the threaded bore of said one of the side walls.

2 Claims, 2 Drawing Figures 56 References Cited UNITED STATES PATENTS 571,266 11 1896 Favrow 100/171 ux FOREIGN PATENTS OR APPLICATIONS 277,055 7/1914 Germany o 8a -vi-: l: l-

i 1 I Z DEVICE FOR ADJUSTING THE SPRING FORCE ON FOLDING ROLLERS a The present invention relates to a device for adjusting the spring force with which two axially parallel folding rollers supported in swivel bearings are pressed against each other, preferably for sheet folding machines.

There are known devices in which the folding rollers are pressed against each other by compression springs. Change in the spring pressure is possible in this case only as a function of the distance between the folding rollers which has been established in each case.

German Patent No. 277,055 shows one such device. In this case both the folding roller bearings and the bushings receiving the compression springs are changed in their position by means of an adjustment fork which has wedge surfaces, by the adjustment thereof by means of a threaded spindle. If the wedge surfaces of the folding roller bearings and of the sleeves are parallel, then the spring tension remains constant for all adjustments of the rollers. If the angle of inclination differs, then the spring pressure also changes upon adjustment of the distance between the folding rollers.

There is also known a folding device Pat. No. 1,231,723 of the Federal Republic of Germany, in which the fold gap betweenthe folding rollers is adjusted by means of spring-loaded double-armed levers.

The double-armed levers are in this case actuated via adjustment screws having oblique surfaces. A change in the spring pressure acting via the double-armed levers on the folding rollers is possible in this connection only sufficient to maintain constant the spring pressure, with which the folding rollers are pressed against each other or to change them only within narrow limits as a function of the slot width between the folding rollers. With material of the same thickness but of different nature, it is, for instance, necessary to change the spring pressure with which the folding rollers are pressed against each other, although the distance between the folding rollers remains the same. This requirement cannot be satisfied by the known devices.

It is one object of the present invention to provide a device [-1, in which the spring force of two folding rollers acted on by a compression spring can be adjusted both dependent on and independently of the width of the folding slot. In addition to this, assurance is to be provided that the force acting on the folding rollers is absolutely uniform and can be varied in a simple manner from one side of the machine.

It is another object of the present invention, to provide a device, wherein compression springs are provided on a shaft between swivel bearings and adjustable abutments. The shaft, provided on both sides with a scale and the pin, the amount of the spring force can be determined.

The advantage of this apparatus resides particularly in the fact, that an absolutely uniform adjustment of the spring pressure on both sides of the folding rollers is possibleand the adjustment of both folding rollers is afiected from only one side of the machine. The adjustment of the spring force acting on the folding rollers can now be effected with substantial consideration of the difference in strength and stiffness of the materials to be worked.

It is furthermore possible, for instance, when producing a third fold, to change the spring force uniformly on the side where the fold which is already present is pulled through between the folding rollers and thus assure a uniform passage of the folded sheet. Another advantage of this apparatus resides in its simple construction and operation.

With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be'already understood in connection with the accompanying drawings, in which:

FIG. 1 is an elevation of one side of the support of the folding rollers, shown partly in cross-section; the rear side which has not been shown is exactly similar to the side shown; and

FIG. 2 is a perspective view partly broken away of one end of the support.

Referring now to the drawings, folding rollers l and l' are supported in swivel bearings 2 and 2'. The swivel bearings 2 and 2 are connected with bearing pins 3 and 3' and are swingable around the the latter. In addition to this, a shaft 4 is passed through a bore in the swivel bearings 2 and 2'. The bore of the swivel bearings 2 and 2' is in this connection so large, that the necessary range of swing can be maintained.

On the shaft 4 compression springs 7 and 7' are provided between adjustable abutments 5 and 6 and the swivel bearings 2 and 2. By means of the adjustable abutment 5 on the shaft 4 and the adjustable abutment 6 which is connected with the bushing 8, it is possible to make the spring force of the compression spring 7 and 7' equal to each other. The shaft 4, provided at both ends with a thread, is supported in a threaded bore of the side wall 9 and in the threaded bore of the bushing 8. The bushing 8 is arranged fixed against rotation but axially displaceable on the side wall 10. The pitch of the thread in the bushing 8 is twice as great as in the threaded bore of the opposite side wall 9. On the operating side the journal 11 of the shaft 4 extends through the side wall 9 and the annular scale 12 fastened to it. As shown in FIG. 2, journal 11 is provided with a longitudinal marking and a plurality of transverse markings 1 1' which, together with the markings 12a of the annular scale 12, give information as to the revolutions effected of the shaft 4 and thus as to the value of the spring pressure force upon adjustment.

The zero position is reached when the end 13 of the shaft 4 resets against the annular scale 12. By turning the shaft 4, the latter is moved in an axial direction as a function of the pitch of the thread in the side wall 9. Since the bushing 8 is fixed against rotation, but is axially displaceable in the side wall 10 and has in its bore a thread 8a with twice as large a pitch as the thread 9a in the threaded bore of the opposite side wall 9, the bushing 8, upon rotation of the shaft 4, is removed axially by the same distance but in a direction opposite the shaft 4. The distance between the abutments 5 and 6 and the swivel bearings 2 and 2 thus change, i.e., the

two compression springs are pulled apart or pressed together respectively, and the spring force acting on the swivel bearings 2 and 2' decreses or increases, respectively. In addition to this, this spring force is also affected to a slight extent by the adjustment of the distance between the folding rollers. The adjustment of the distance between the folding rollers is effected in the manner that in a way not shown in in detail the swivel bearings 2 and 2 are swung around the bearing pins 3 and 3'.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense.

I claim:

1. A device for adjusting the spring force pressing two axially parallel folding rollers, comprising a shaft,

two folding rollers having parallel axes and supported in swivel bearings,

an abutment means spaced apart from each of said swivel bearings and mounted on said shaft, a compression spring disposed between each of said folding rollers and said abutment means, respectively, two side walls, said shaft having a thread at each of its ends, one of said ends of said shaft being threaded in a bore of one of said side walls, the other of said ends of said shaft being threaded in a threaded bore of a bushing, said bushing being disposed non-rotatably and axially displaceably in a bore of the other of said side walls, and the pitch of said thread bore of said bushing being twice as great as the pitch of said threaded bore of said one of said walls. 2. The apparatus, as set forth in claim 1, wherein said one of said ends of said shaft has a journal projecting through said one of said side walls, an annular scale loosely mounted on said journal outside of said one of said walls, and said annular scale and said journal have markings indicating the force of said springs.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 786 742 Dated Janua'gy 22 1974 Inventor-(s) Klaus HertTiCh' It is certified that errorappears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On thecover sheet, in the heading, the assignee's name should read as follow s; I

- VEB POLYGRAPH LEIPZIG KOMBINAT FUR POLYGRAPHISCHE MASCHINEN UND 'AUS RUS TUNGE N Signed and Sealed this 18th day of June l9'7 4.

' (SEAL) Attest: v

EDWARD M. FLETC HIER,JR. 1 V I I c. MARSHALL DANN Attesting Officer f i Commissioner of Patents ORM PO-1OSO (10-69) USCOMM-DC scan-ps9 

1. A device for adjusting the spring force pressing two axially parallel folding rollers, comprising a shaft, two folding rollers having parallel axes and supported in swivel bearings, an abutment means spaced apart from each of said swivel bearings and mounted on said shaft, a compression spring disposed between each of said folding rollers and said abutment means, respectively, two side walls, said shaft having a thread at each of its ends, one of said ends of said shaft being threaded in a bore of one of said side walls, the other of said ends of said shaft being threaded in a threaded bore of a bushing, said bushing being disposed non-rotatably and axially displaceably in a bore of the other of said side walls, and the pitch of said thread bore of said bushing being twice as great as the pitch of said threaded bore of said one of said walls.
 2. The apparatus, as set forth in claim 1, wherein said one of said ends of said shaft has a journal projecting through said one of said side walls, an annular scale loosely mounted on said journal outside of said one of said walls, and said annular scale and said journal have markings indicating the force of said springs. 